1. Field of the Invention
The present invention relates to a signal detecting apparatus for detecting transmission signals transmitted by a power receiving apparatus in a wireless power transmitting system, and a wireless power transmitting apparatus having the signal detecting apparatus for detecting transmission signals.
2. Description of the Related Art
Generally, various portable terminals such as cellular phones, smart phones, personal digital assistants (PDAs), and the like, has been mounted with a power receiving apparatus for supplying an operation power thereto.
The power receiving apparatus, which is charged with a power supplied from an external charging apparatus and supplies the charged power as an operation power to the portable terminal to operate the portable terminal, may comprise a battery cell module charged with the power, a charging and discharging circuit which uses the power supplied from the external charging apparatus to charge the battery cell module and discharges the power charged in the battery cell module to supply the discharged power as the operation power to the portable terminal, and the like.
In a known method of electrically connecting the charging apparatus to the power receiving apparatus, a terminal through which the power is outputted from the charging apparatus is directly connected to a terminal to which the power is inputted into the power receiving apparatus through a cable, a connector, or the like.
With the terminal connection method, the terminal of the charging apparatus and the terminal of the power receiving apparatus have different potential differences. Therefore, when the terminals are connected to or disconnected from each other, an instantaneous discharging phenomenon occurs. This instantaneous discharging phenomenon causes abrasion of both terminals. In addition, if foreign materials have accumulated in the terminals, the foreign materials may be heated by the instantaneous discharging phenomenon, such that there is a risk of an accident such as a fire, or the like.
Further, the power charged in the battery cell module in the power receiving apparatus is naturally discharged into the environment through the terminal of the power receiving apparatus due to moisture, or the like, such that lifespan of the power receiving apparatus may decrease and performance of the power receiving apparatus may deteriorate.
Recently, a wireless power transmitting system which wirelessly transmits the power has been suggested in order to solve several problems of the terminal connection method as described above.
In known wireless power transmitting systems, a wireless power transmitting apparatus wirelessly transmits the power using electromagnetic induction. A power receiving apparatus then receives the power wirelessly transmitted by the wireless power transmitting apparatus and charges the received power into the battery cell module.
Many have sought to improve the described wireless power transmitting system such that the wireless power transmitting apparatus wirelessly transmits the power stably at high efficiency, and such that the power receiving apparatus receives as much of the power transmitted by the wireless power transmitting apparatus as possible to charge the power in the battery cell module.
In the known wireless power transmitting system described above, the power receiving apparatus generates a transmission signal, including a unique ID signal and a power charging information signal indicating the power charged in the battery cell module, and transmits the transmission signal to the wireless power transmitting apparatus through a power receiving coil, and the wireless power transmitting apparatus receives the transmission signal through a power transmitting coil.
Since a voltage and a current of the power transmitting coil of the wireless power transmitting apparatus are changed according to the transmission signal transmitted by the power receiving apparatus through the power receiving coil, the wireless power transmitting apparatus may detect the voltage and the current of the power transmitting coil using a voltage sensor, a current sensor, a current transducer, and the like, and determines the detected voltage and current by using a detecting circuit or the like to detect the transmission signal transmitted by the power receiving apparatus.
Therefore, a configuration of a circuit which detects the transmission signal transmitted by the power receiving apparatus is significantly complicated, such that manufacturing costs increase. Furthermore, there is a limited precision in detecting the transmission signal.